AU2010235881A1 - Method and system for analyzing radio performance during over-the-air operation - Google Patents

Description

AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Standard Patent Applicant(s): Locus Location Systems, LLC Invention Title: Method and system for analyzing radio performance during over the-air operation The following statement is a full description of this invention, including the best method for performing it known to me/us: -2 METHOD AND SYSTEM FOR ANALYZING RADIO PERFORMANCE DURING OVER-THE-AIR OPERATION CROSS-REFERENCE TO RELATED APPLICATIONS This patent application claims priority to the 5 provisional application filed on October 18, 2009, assigned application number 61/252,693 and entitled Method and System for Analyzing Radio Performance During Over The-Air Operation. BACKGROUND OF THE INVENTION 10 The ability of a communications transmitting device to operate according to its specifications is crucial to proper communications between the transmitting device and the receiving device. Often the user does not realize the transmitting device is not operating according to its 15 specification until it fails completely. When the device fails, it must be taken out of service, the problem diagnosed and the device repaired. The present invention overcomes this limitation by advising the user when a specification parameter is not met, although the device 20 may continue to operate within the network at a degraded level. BRIEF DESCRIPTION OF THE FIGURES The present invention can be more easily understood and the advantages and uses thereof more readily apparent 25 when the following detailed description of the present invention is read in conjunction with the figures wherein: The Figure is a block diagram of the system of the present invention. In accordance with common practice, the various 30 described features are not drawn to scale, but are drawn to emphasize specific features relevant to the invention. 24423501 (GHMatters) 18/10/10 - 3 Like reference characters denote like elements throughout the figures and text. DETAILED DESCRIPTION OF THE INVENTION Before describing in detail the particular method and 5 system for analyzing performance of a radio or transmitting device during over-the-air operation according to the present invention, it should be observed that the present invention resides in a novel and non obvious combination of structural elements and method 10 steps. Accordingly, these elements have been represented by conventional elements and steps in the drawings and specification. The elements and process steps conventionally known in the art are described in lesser detail, and elements and steps pertinent to understanding 15 the invention are described in greater detail. The following preferred embodiments are an application of the present invention and are not intended to define limits of the structure or use of the invention, but only to provide exemplary constructions. Many variations can be made to 20 the design within the scope of the presented claims. The present invention determines the "health" of a transmitting device (e.g., a mobile, portable or stationary transmitter or transceiver) that emits a radio frequency signal for receiving by a receiving device 25 (e.g., a receiver, a transceiver), including transmitting and receiving devices operating in a network. The network may include, but is not limited to, a WiFi network, a trunked radio network, a cellular telephone network, a paging network, a WiMax network, an 802.11x network and a 30 Zigbee network. The teachings of the invention can be applied to transmitting and receiving devices operating in digital and analog networks (where the analog networks include such devices as conventional two-way radios and AM or FM transmitters). 2442350_1 (GHMatters) 18/10/10 - 4 The "health" of each device, which is important to ensure that a user can effectively communicate with others in the network, is determined while the device is in an over-the-air operating mode. Bench tests for transmitting 5 devices are known in the repair art. Unlike the known art, the present invention does not require removing the device from active service to evaluate the "health" of the device. Instead, the present invention allows a network operator or a device user to assess the "health" of the 10 device during normal operation. When used in the present application, the "health" of a device refers to its performance in accordance with applicable performance specifications as determined by the device manufacturer or as determined by the user or 15 network provider. That is, the network provider may require tighter tolerances for certain operational parameters due to the characteristics of its network. A failed component or other element of the device may degrade its performance and/or cause its parameters to 20 vary from the specification values. A significant degradation or a significant variation from the specification may prevent the device from communicating with other devices on the network. According to the present invention, the transmitting devices are tested 25 during over-the-air operation and any variance from the applicable specifications is identified. The device can then be removed from service for repair. As used herein the term "radio" refers to any transceiver (or transmitter) transmitting or transmitting 30 and receiving RF signals. Mobile and portable transceivers used in public safety trunked networks are commonly referred to as radios. One application of the present invention applies to radios operating in a trunked radio system that includes a 35 location-determining subsystem for determining the 2442350_1 (GHMatters) 18/10/10 -5 location of any transmitting radio. In this application, the "health" of each radio is important to accurately locate the radio and its operator. The teachings of the invention can be employed by a 5 network operator to determine the "health" of transmitting devices operating within its network or the "health" of a transmitting device can be determined irrespective of any network in which the transmitting device operates. Use of the system of the invention can identify incipient and 10 real-time transmitting device problems to reduce both transmitting device and network downtime, improve the "health" of the network, increase network capacity and improve other aspects of network performance (e.g., location accuracy for a transmitting device operating in a 15 radio-location system). To identify incipient problems, the user (or network operator) can set a relatively tight tolerance for transmitting device operation; any performance parameters outside this range, while not indicative of a failure, may 20 be evidence of a potential problem. Thus parameters outside the user-defined range may trigger an incipient problem alert. The invention can also determine whether a transmitting device is operating according to pertinent 25 regulations promulgated by a regulatory agency, such as the U.S. Federal Communication Commission or similar regulatory agencies of other countries. These regulations dictate the operating requirements of both licensed and unlicensed transmitting devices. The invention can also 30 determine if a transmitting device operates within its published specifications, apart from any applicable government regulations. The system and method of the present invention (commercially referred to as a DiagnostX System) is a 35 field diagnostic tool that verifies and/or determines the 2442350_1 (GHMatters) 18/10/10 - 6 "health" of transmitting devices using over-the-air transmissions from the transmitting devices. For example, when a radio in a trunked radio network transmits (on an inbound channel), a request for a working channel (i.e., 5 the channel or frequency for carrying a subsequent communication with another radio in the network) to a network controller, the system of the invention captures the transmitted waveform on the inbound channel and analyzes the waveform for possible failures, problems or 10 out-of-spec parameters. The system can also listen to the outbound control channel (over which the radio is advised to a working channel by the network controller) and follow the radio to its assigned working channel to capture and analyze working channel transmissions. 15 The system of the present invention captures inbound and outbound control channel signals and working channel signals to measure operational characteristics of the radio when operating in a transmitting mode and to detect potential radio transmission problems. The trunked radio 20 system operator can remove the radio from service for repair or undertake other maintenance actions as deemed advisable. The signal measurement and analysis features of the invention are intended to reduce radio failures in the field and to identify suspect radios before they fail. 25 When used in conjunction with a location-determining system, the present invention also improves the accuracy of the determined locations by ensuring that each radio is operating according to its specifications. As applied to the trunked radio system, a better operating radio can 30 also reduce the number of control channel retries and therefore increase the system throughput or capacity. Generally, one parameter determined by the system of the invention is a received signal strength indicator (RSSI) value. This value must exceed a minimum RSSI to 35 permit meaningful analysis of the signal parameters and transmitter operating characteristics as determined by the 2442350_1 (GHMatters) 18/10/10 - 7 present invention. In one embodiment the minimum value is -95 dBm. Signals with RSSI values less than -95 dBm can be ignored or if analyzed can be notated with an indication that the RSSI value was below the required 5 minimum value. To set up the radio diagnostic system, an identifier for each radio is entered into the database. The operating characteristics or parameters are also entered manually or selected from a presented menu. These 10 specifications for individual radios are determined by the operating for that radio, e.g., transmission type, protocol type. For example, each protocol may have a different specification and a different range of permitted deviations from that specification. Further, a first 15 specification range may be established to identify potential problem radios. An operational parameter within the first range indicates a suspect radio. A second specification range may be established to identify failed radios. An operational parameter within the second range 20 indicates a failed radio that should be immediately removed from service for repair. The Figure illustrates a block diagram of the system of the invention. The system includes one or more signal sensors (referred to as a DSP and DiagnostX Manager (DM) 25 in the Figure) 12 that receive RF signals from transmitting radios 14 and measures characteristics of the signal to extract desired operational metrics or operating characteristics of that radio. In one embodiment of the invention, each receiving site or sensor in a network 30 employs at least one directional antenna or a plurality of antennas that provide diversity reception and may thereby increase a signal strength of a received signal. Each sensor further includes, in an addition to the at least one antenna, a receiver, a digital signal processor, a 35 precision oscillator and a general purpose processor. These devices cooperate, under control of the processor, 2442350_1 (GHMattera) 18/10/10 -8 to measure various signal parameters of the transmitted signal as required to extract the transmitter operating characteristics, as identified below. An identifier associated with each radio and included 5 in each signal transmitted by that radio is used to link the determined transmitter operating characteristics to the transmitting radio. A database 20 stores the radio identifiers for radios to be monitored (and in one embodiment a list of 10 identifiers for radios that are not to be monitored). The database 20 stores the pertinent specifications, desired operating characteristics and specifications ranges for each radio. The database also stores the actual operating characteristics for each radio, where the actual operating 15 characteristics are determined from the signals transmitted from the pertinent radio as those signals are received and analyzed by the system of the present invention. The sensor measurements are input to a DiagnostX 20 Analyzer (DA) 18 that performs calculations and determines whether the signal measurements indicate that one or more operating characteristics of the radio exceed the pertinent specification ranges for that radio. When certain ranges are exceeded the radio may be flagged as 25 suspect and when other ranges are exceeded this may warrant flagging the radio as failed. Results from the DA 18 are displayed on a graphical user interface (GUI) 22 under control of a DiagnostX Viewer (DV) 26 that pulls data for the GUI 22 from the DA 30 18 and the database 20. For example, the GUI 22 may display a radio identifier and signal measurements associated with the identified radio. The system can also identify (highlight) and display pertinent information for any radio with potential or incipient problems, including 35 a general textual description of the problem. 2442350_1 (GHMatters) 18/10/10 - 9 From the DA 18, the analysis results are also stored in the database 20 for later retrieval and/or additional analysis. The database 20 can be searched by radio identification number to retrieve performance data for 5 selected radios. After a radio has been repaired, the collected performance parameters can be cleared from the database 20 as they are no longer relevant after radio repair. The system can also target specific radios for 10 additional and more detailed over-the-air or bench analysis. Such radios can also be identified in the database 20. In one embodiment, performance data for the targeted radios can be collected more frequently than the other radios in the database. 15 The system generates, displays, and prints numerous reports including but not limited to: Good radios, i.e., those that satisfy predefined operating thresholds or satisfy associated specifications Suspect radios as determined from standard industry 20 conformance testing and operational specifications. Radios emitting a weak signal, where weak is defined as an RSSI below a predetermined threshold or below the specification for the associated radio. Radios with an insufficient number of transmissions 25 to permit an accurate determination of the radio's health. Radios not in regular use Other reports according to user-defined subject matter Waveform visualization 30 Bit-field visualization (i.e. a packet sniffer) An analysis of the received signal and its waveform provides information on the operational aspects of each radio, including but not limited to the following operational attributes. 35 RF frequency accuracy 2442350_1 (GHMattere) 18/10/10 - 10 RF frequency offset (i.e., offset from an assigned frequency) Timing of RF frequency offsets relative to a beginning of a message 5 RF frequency offset variations throughout a message Frequency deviation of the modulated signal (i.e., the difference between the center frequency of the received signal and the modulated frequency) Range of frequency deviations over time 10 Maximum frequency deviation Unexpected amplitude variations during a message Symbol Frequency Error Symbol Clock Error Modulation Fidelity 15 Bit Error Rate Conformance to packet structure specifications Baud rate changes during a message Spurious emissions Received signal strength indicator (RSSI) 20 Consistent low power level irrespective of radio location High bit error rate irrespective of radio location Battery charge Probable emission mask non compliance 25 Communication retries that exceed a user-defined threshold (as applied to a trunked network). This parameter can also be determined with respect to a specific receiving site in a trunked network, i.e., whether a specific site on the network is experiencing a 30 substantial number of retries. An unexpectedly low received signal strength based on the location of the radio and the location of the receiving sensor To assist with the analysis of each radio, the 35 operator can define different operational metric thresholds (e.g., frequency offset, frequency deviation) 2442350_1 (GHMattere) 18/10/10 - 11 for one or more radios by reference to the radio identifier. This feature thus allows different thresholds to be established for different radios in the network. The system can also rank the radios from those with the 5 best performance to those with the worst. A radio exhibiting an operating measurement that exceeds a threshold is indicated on the GUI 22. These radios may be classified as suspect or failed. In one embodiment the number of analyzed transmissions and the 10 time period over which the data is collected must satisfy minimum thresholds before the radio can be identified as suspect or failed. The system operator can also determine and configure the system with the length of time the historical 15 operational data is stored (e.g., a storage time parameter such as last year, last six months, etc.), the frequency at which the performance data is collected (e.g., one daily performance snapshot, weekly, monthly) and the performance data measured during each snapshot. 20 The system can generate and send e-mail alerts to users and system operators. For example, each morning an email listing the worst performing or suspect radios can be sent to system operators or to the user of each listed transmitting device. The users of the listed radios and 25 the system operators should consider these radios when communicating with or trying to locate any of the listed radios. The alert criteria are also user-defined (e.g., frequency of emails, email distribution list). If the system operator is interested in the 30 performance of only a subset of the radios, the operator generates a list of the radios and configures the system to monitor the performance of only the listed radios. The system can also store and display: 2442350_1 (GHMatters) 18/10/10 - 12 A minimum RSSI threshold (e.g., -95 dBm or greater) before operational data is collected A median calculation on the collected data to statistically eliminate any outliers for a radio. 5 Radio repair dates tied to a radio identifier (preferably a radio serial number or another unique radio identifier). A repair technician enters the radio identifier into the system before beginning the repair and a system-generated date is used as the repair date. When 10 a repair date is entered the historical performance data and all radio transmissions are cleared A suspect radio can be cleared of all recorded performance measurements and events to restart the collection and evaluation process for the radio. The 15 system-generated date/time is used as the "clear" date Store the previous n performance data measurements for every radio Maintain lists and pertinent data that indicate the health of each radio according to the parameters that the 20 user or system operator defines for a suspect, failed and a properly operating radio. For example, the lists can indicate a radio always transmitting signals below a user defined RSSI threshold, above a user-defined threshold but based on fewer than n measurements, and a subjective 25 judgment as to the radio's health (e.g., good or suspect) and the metrics on which the judgment is based. The user or system operator can also define the contents of any list and data reporting requirements for any radio. Generate or use an operator-provided list of radio 30 identification information that identifies radios for which performance data has not been collected Ensure the radios meet FCC mandated performance requirements Install software updates or synthetic instrumentation 35 via an Internet connection or manually from a CD or USB drive 2442350_1 (GHMatters) 18/10/10 - 13 When a signal from a radio is detected (referred to as an event), radio identification information, date and time information, and measured operational characteristics for that radio are determined and stored. The operational 5 parameters are analyzed to determine the "health" of the radio. Tracking the time the event is recorded allows the system to time-align events if multiple sensors are used to record the radio performance data. The system can track radios by serial number, radio 10 ID, or another unique identifier. This is useful in systems where radios are reconfigured with different identifiers because it allows all historical performance information to link to the same physical radio. In one embodiment, after a location of the radio is 15 determined, by a radio-location system separate from the diagnosis system of the invention, the RSSI value can be used as one parameter to assess the "health" of the radio. Other parameters that are location-dependent can also be used once the location has been determined. 20 Although the invention has been shown and described with respect to a certain preferred embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding this specification and the 25 annexed drawing. In particular regard to the various functions performed by the above described components (assemblies, devices, circuits, etc.), the terms used to describe such components are intended to correspond, unless otherwise indicated, to any component that performs 30 the specified function of the described component (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure that performs the function in the illustrated exemplary embodiments of the invention. In addition, while a 35 particular feature of the invention may have been 24423501 (GHMatters) 18/10/10 - 14 disclosed with respect to only one of several embodiments, such feature may be combined with one or more other features of the other embodiments as may be desired and advantageous for any given or particular application. 5 In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, 10 i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. It is to be understood that, if any prior art publication is referred to herein, such reference does not 15 constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country. 2442350_1 (GHMatters) 18/10/10

Claims (21)

1. An apparatus for determining operating characteristics of radio-frequency (RF) transmitting devices while the devices are in normal operation 5 transmitting over-the-air RF signals, the apparatus comprising: at least one signal sensor for receiving the RF signals, each sensor responsive to the RF signals received at a plurality of antennas or received at a directional 10 antenna; an analyzer for determining signal parameters of received RF signals and for determining operating characteristics of the transmitting devices from the signal parameters; 15 wherein each RF signal includes an identifier of the transmitting device, the apparatus using the identifier to link operating characteristics determined from the RF signals to the transmitting device; and a graphical user interface for displaying the 20 operating characteristics for each transmitting device.

2. The apparatus of claim 1 wherein the analyzer further determines one or more transmitting devices satisfying predefined operating thresholds, transmitting devices satisfying specifications applicable to the 25 transmitting device, suspect transmitting devices, transmitting devices transmitting a signal having an RSSI below a predetermined threshold, transmitting devices transmitting a signal having an RSSI below the specification applicable to the transmitting device, 30 transmitting devices having an insufficient number of transmissions from which to determine operating characteristics of the transmitting device, transmitting devices not in regular use, transmitting device reports according to user-defined topics, waveform visualization 35 information and bit-field visualization information. 2442350_1 (GHMatters) 18/10/10 - 16

3. The apparatus of claim 1 wherein responsive to the analyzer, the graphical user interface identifies transmitting devices that have failed and transmitting devices that are suspect. 5

4. The apparatus of claim 1 wherein the signal parameters comprise, RF frequency accuracy, RF frequency offset from an assigned frequency, timing of RF frequency offsets relative to a beginning of a message transmission, RF frequency offset variations throughout a message 10 transmission, frequency deviation of the modulated signal, range of frequency deviations over time, amplitude variations during a message transmission, symbol frequency error, symbol clock error, modulation fidelity, bit error rate, conformance to packet structure specifications, baud 15 rate changes during a message transmission, spurious emissions, RSSI, consistent low power level irrespective of location of the transmitting device, high bit error rate irrespective of location of the transmitting device, battery charge, a number of retries over a predetermined 20 threshold, unexpectedly low RSSI.

5. The apparatus of claim 1 wherein operating characteristics for identified transmitting devices are collected more frequently than operating characteristics for other transmitting devices. 25

6. The apparatus of claim 1 wherein the apparatus is configured with a storage time parameter for identifying a period of time for storing the operating characteristics and configured with a data collection frequency parameter for identifying a frequency at which the operating 30 characteristics are determined.

7. 7.The apparatus of claim 1 wherein the apparatus includes a list of identifiers of transmitting devices for which signal parameters are to be determined. 8. The apparatus of claim 1 wherein the frequency of monitoring 2442350_1 (GHMatters) 18/10/10 - 17 and analyzing the signal parameters is user-defined for each transmitting device.

8. The apparatus of claim 1 wherein the transmitting device comprises a transmitting device operating in a 5 trunked network and the apparatus monitors at least one of a request from the transmitting device to a network controller for an inbound channel, a message from the network controller advising the transmitting device of an assigned inbound channel and an inbound channel carrying 10 transmissions from the transmitting device.

9. The apparatus of claim 1 wherein the apparatus operates in conjunction with a location-determining system for determining location of transmitting devices in a trunked radio network, and wherein the apparatus advises 15 the location-determining system of performance of the transmitting devices in the trunked radio network.

10. The apparatus of claim 10 wherein predefined operating thresholds for a transmitting device are modified responsive to a determined location for the 20 transmitting device.

11. The apparatus of claim 1 further comprising a component for issuing email messages including operating characteristics for identified transmitting devices.

12. The apparatus of claim 1 further comprising a 25 component for issuing email alerts identifying failed or suspect transmitting devices.

13. The apparatus of claim 1 wherein a "health" of a transmitting device is determined by comparing the operating characteristics of the transmitting device with 30 performance specifications for the device.

14. The apparatus of claim 1 wherein a "health" of a transmitting device is determined by comparing the operating characteristics of the transmitting device with 2442350 1 (GHMatters) 15/10/10 - 18 governmental regulations applicable to performance of the transmitting device.

15. The apparatus of claim 1 wherein the transmitting device comprises a mobile, portable or stationary 5 transmitting device or a mobile, portable, or stationary transceiver.

16. The apparatus of claim 1 wherein the transmitting device is operative in a communications network, further comprising one of a WiFi network, a trunked transmitting 10 device network, a cellular telephone network , a paging network, a WiMax network, an 802.11x network and a Zigbee network.

17. The apparatus of claim 1 wherein the device transmits signals in at least one of digital and analog 15 formats.

18. The apparatus of claim 1 further comprising a database for storing information related to the operating characteristics, the information comprising one or more of a statistics related to the operating characteristics for 20 a transmitting device, past repair dates for a transmitting device, transmitting devices for which no operating characteristics have been determined, user defined information.

19. The apparatus of claim 1 further comprising a 25 database from which the operating characteristics for a transmitting device are deleted after the transmitting device is repaired.

20. The apparatus of claim 1 wherein the at least one signal sensor comprises at least one antenna, a receiver, 30 a digital signal processor, a precision oscillator and a general purpose processor, cooperating to measure signal parameters of the RF signals from which the operating characteristics of the transmitting device are determined. 2442350_1 (GHMatters) 18/10/10 - 19

21. A method for determining operating characteristics of a radio-frequency (RF) transmitting device while the device is in normal operation transmitting over-the-air RF signals, the method comprising: 5 22. receiving RF signals at at least one signal sensor, each sensor responsive to the RF signals received at a plurality of antennas or received at a directional antenna; measuring signal parameters of received RF signals; 10 determining operating characteristics of the transmitting device from the signal parameters; wherein each RF signal includes an identifier of the transmitting device, using the identifier to link operating characteristics determined from the RF signals 15 to the transmitting device; and displaying the operating characteristics for the transmitting device. 2442350_1 (GHMattere) 18/10/10